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Compaction-induced stress in geosynthetic-reinforced granular base course--A discrete element model

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Journal of Rock Mechanics and Geotechnical Engineering 2018年第4期10卷 669-677页

作者： Te Pei xiaoming yang School of Civil and Environmental Engineering Oklahoma State UniversityStillwaterUSA

A discrete element method(DEM) model was used to simulate the development of compaction-induced stress in a granular base course, with and without geogrid reinforcement. The granular base course was modeled as a mixture of uniformly sized triangular particles. The geogrid was modeled as a series of equally spaced balls that interact with each other through long-range interaction contacts. The longrange interaction contact was also used to simulate a deformable subgrade. The compactor was modeled as a solid cylinder rolling at a constant speed. The DEM model shows that the geogridreinforced granular base course gains additional compaction-induced stress due to the residual tensile stress developed in the geogrid. The residual tensile stress in the geogrid increases with the number of compaction passes. Parametric analyses were also conducted to assess the effects of geogrid stiffness and subgrade modulus on the compaction-induced stress.

关键词： Compaction Geosynthetics Granular soils Numerical analysis

An assessment of the geometryeffect of geosynthetics for basecourse reinforcements

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International Journal of Transportation Science and Technology 2012年第3期1卷 247-257页

作者： xiaoming yang School of Civil and Environmental Engineering Oklahoma State University207 Engineering SouthStillwaterOK 74078USA

Geosynthetic-reinforced base course is potentially a cost-effective solution for flexible *** the recent advance in the mechanistic-empirical pavement design in the UnitedStates,there is a need to develop the next generation design method for geosynthetic-reinforcedbases in flexible *** develop such a design method requires an improvedunderstanding about the mechanistic behavior,especially the in-plane elastic behavior,*** this paper,the geometry effect of geosynthetics was *** author firstreviewed recent experimental and numerical *** equations based on cellularmaterial mechanics were presented for determining the in-plane elastic properties *** analytical equations were used to evaluate a few geosynthetics with *** results showed that,with the same polymeric material and typical productgeometries,the geocell has a better confinement effect than geogrids,and the triaxial geogridwith a triangular aperture has a better confinement effect than the biaxial geogrid with arectangular *** was also demonstrated that the traditional uniaxial tensile modulus maybe a poor indicator of the effectiveness of geosynthetics for base course reinforcements.

关键词： effect bases modulus

Tensile and Isothermal Fatigue Behaviors of Mg-12Gd-3Y-0.5Zr Alloy at High Temperature

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Journal of Materials Science & Technology 2009年第6期25卷 731-737页

作者： xiaoming yang Huajie yang Fan yang Shuming Yin Wei Wang Shouxin Li Qudong Wang Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China National Engineering Research Center of Light Alloys Net Forming Shanghai Jiao Tong University Shanghai 200020 China

Tensile and isothermal fatigue tests were carried out on an as-rolled Mg-12Gd-3Y-0.5Zr alloy and its heat-treated counterpart at different temperatures. The experimental results show that the ultimate tensile strengths of two alloys decrease very slowly with increasing temperature up to 200℃. The ultimate tensile strength of heat-treated Mg-12Gd-3Y-0.5Zr is slight lower than that of as-rolled counterpart; however, the fatigue strength of heat-treated alloy is higher. The mechanism of fatigue failure was investigated by scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. It shows that cyclic slip combined with environmental effect may be the main crack initiation mechanism.

关键词： Mg-12Gd-3Y-0.5Zr Isothermal fatigue Fatigue strength Tensile strength

Yellow-Fluorescence Carbon Dots Employed for pH Sensing and Detection of Tigecycline

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Chinese Journal of Chemistry 2023年第24期41卷 3677-3683页

作者： Jingwen Zhao Junchen Wang Linggao Zeng Sen Zhou xiaoming yang College of Pharmaceutical Sciences Southwest UniversityChongqing400715 China Chongqing Academy of Metrology and Quality Inspection Chongqing401121 China NMPA Key Laboratory for Quality Monitoring of Narcotic Drugs and Psychotropic Substances Chongqing Institute for Food and Drug ControlChongqing401121 China

Long-wavelength fluorescence carbon dots (CDs) show great importance in multiple fields,especially for the biochemical ***,we proposed one type of CDs doped with nitrogen and sulfur through the hydrothermal method,which exhibited obvious yellow-fluorescence in aqueous ***,the fluorescence intensity of CDs decreased with pH decreasing in the acidic range,thus a linear relationship between pH and fluorescence intensity was established,exhibiting the potential of pH ***,introducing tigecycline into CDs resulted in their decreased fluorescence,thus,we further established a strategy of detecting tigecycline with the concentration range of 200 μM to 7 ***,we elucidated the static quenching as the major mechanism for CDs responding tigecycline,which was induced by the formed new complex between CDs and ***,the practicality of the method was verified by examining the recovery of tigecycline in the actual lake-water samples.

关键词： Yellow-fluorescence Tigecycline Nanostructures Quantum dots Sensors

Inverse Analysis of Pavement Structural Properties Based on Dynamic Finite Element Modeling and Genetic Algorithm

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International Journal of Transportation Science and Technology 2013年第1期2卷 15-30页

作者： Xiaochao Tang xiaoming yang Louisiana Transportation Research Center Louisiana State University4101 Gourrier AvenueBaton RougeLA 70808USA School of Civil and Environmental Engineering Oklahoma State University319D Engineering SouthStillwaterOK 74078USA

With the movement towards the implementation of mechanistic-empirical pavement design guide(MEPDG),an accurate determination of pavement layer moduli is vital for predicting pavement critical mechanistic responses.A backcalculation procedure is commonly used to estimate the pavement layer moduli based on the non-destructive falling weight deflectometer(FWD)*** of flexible pavement layer properties is an inverse problem with known input and output signals based upon which unknown parameters of the pavement system are *** this study,an inverse analysis procedure that combines the finite element analysis and a population-based optimization technique,Genetic Algorithm(GA)has been developed to determine the pavement layer structural properties.A lightweight deflectometer(LWD)was used to infer the moduli of instrumented three-layer scaled flexible pavement *** the common practice in backcalculating pavement layer properties still assumes a static FWD load and uses only peak values of the load and deflections,dynamic analysis was conducted to simulate the impulse LWD *** recorded time histories of the LWD load were used as the known inputs into the pavement system while the measured time-histories of surface central deflections and subgrade deflections measured with a linear variable differential transformers(LVDT)were considered as the *** a result,consistent pavement layer moduli can be obtained through this inverse analysis procedure.

关键词： analysis load pavement

Synthesis and biological evaluation of 8-substituted and deglucuronidated scutellarin and baicalin analogues as antioxidant responsive element activators

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Science China Chemistry 2011年第10期54卷 1565-1575页

作者： yang Ping KONG XiangZhen CHENG ChangMei LI ChangYan yang xiaoming ZHAO Xing'E Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology Ministry of Education Tsinghua University Beijing 100084 China Academy of Military Medical Sciences Beijing 100850 China Jiangsu Simcere Pharmaceutical Research Institute Nanjing 210042 China

Flavonoids are important bioactive dietary compounds, which are proved to be antioxidant responsive element (ARE) activators to defend against electrophilic toxicants and oxidative stress. The activators induce ARE gene transcription through Nrf2 factor, a major transcriptional stimulator of cytoprotective genes, relieved from a Keap1 complex. In this report, based on the structures of two flavonoids, scutellarin and baicalin, which are extracted from two common Chinese plants Dengzhanhua (Erigeron breviscapus (vant) Hand-Mazz) and Huangqin (Scutellaria baicalensis Georigi), respectively, we synthesized several 8-substituted and deglucuronidated analogues and identified the ARE activation effects of these flavonoids. We found that the Baicalin, deglucurnonidated Baicalin and diaza cyclopenta derivative were more active. Their dose-dependent upregulation activities of ARE and NQO1 and induction effects of Nrf2 were testified. The results presented that these three analogues had good upregulation effects on ARE, and they could be potentially utilized in relieving oxidative stress, upon further neuroprotective tests.

关键词： Scutellarin Baicalin ARE activator Nrf2 NQO1

A new technique for automatically locating the center of tropical cyclones with multi-band cloud imagery

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Frontiers of Earth Science 2019年第4期13卷 836-847页

作者： Xiaoqin LU Hui YU xiaoming yang Xiaofeng LI Jie TANG Shanghai Typhoon Institute China Meteorological AdministrationShanghai 200030China Ocean Department Shanghai Ocean UniversityShanghai 201306China CAS Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of SciencesQingdao 266071China Center for Ocean Mega-Science Chinese Academy of SciencesQingdao 266071China

A spiral cloud belt matching(SCBeM)technique is proposed for automatically locating the tropical cyclone(TC)center position on the basis of multi-band geo-satellite *** technique comprises four steps:fusion of multi-band geo-satellite images,extraction of TC cloud systems,construction of a spiral cloud belt template(CBT),and template matching to locate the TC *** testing of the proposed SCBeM technique on 97 TCs over the western North Pacific during 2012-2015,the median error(ME)was 50 *** independent test of another 29 TCs in 2016 resulted in a ME of 54 *** SCBeM performs better for TCs with intensity above“typhoon”level than it does for weaker systems,and is not suitable for use on high-latitude or landfall TCs if their cloud band formations have been destroyed by westerlies or by *** proposed SCBeM technique provides an additional solution for automatically and objectively locating the TC center and has the potential to be applied conveniently in an operational *** between the Automated Rotational Center Hurricane Eye Retrieval(ARCHER)and SCBeM methods using events from 2014 to 2016 reveal that ARCHER has better location ***,when IR imagery alone is used,the ME of SCBeM is 54 km,and in the case of low latitudes and low vertical wind shear the ME is 45-47 km,which approaches that of ARCHER(49 km).Thus,the SCBeM method is simple,has good time resolution,performs well and is a better choice for those TC operational agencies in the case that the microwave images,ASCAT,or other observations are unavailable.

关键词： tropical cyclone center location geostationary satellite matching technique

Fluorescent carbon dots derived from lactose for assaying folic acid

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Science China Chemistry 2016年第4期59卷 487-492页

作者： Zhangbao Chen Jing Wang Hong Miao Lan Wang Shuang Wu xiaoming yang College of Pharmaceutical Sciences Southwest University

The fluorescent carbon dots were successfully synthesized by simply heating the mixture of lactose and Na OH solution. The as-synthesized carbon dots had been systematically characterized by fluorescence, Fourier transform infrared(FTIR), high resolution transmission electron microscopy(HR-TEM) and ^(13)C NMR. Since the fluorescence of the carbon dots was efficiently quenched by folic acid, the carbon dots were employed as selective fluorescence probes for detecting folic acid, depending on the formation of hydrogen bond among the functional group of folic acid(–OH, –COOH and –NH_2) and –OH and –COOH of the carbon dots. Moreover, the decrease of fluorescence intensity was capable of detecting folic acid in a linear range of 6×10^(-5)–8×10^(-8) mol/L with a detection limit of 1.2×10^(-9)mol/L at a signal-to-noise ratio of 3, suggesting a promising assay for folic acid. Significantly, the practicability of this fluorescence probe to assay folic acid in human urine samples was further evaluated.

关键词： carbon quantum dots fluorescence quenching

Rapid induction of mRNAs for PC3 by partial hepatec-tomy and epidermal growth factor

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Chinese Science Bulletin 2001年第7期46卷 571-574页

作者： WANG Ge WANG Siying XU Wangxiang yang xiaoming Institute of Radiation Medicine Beijing 100850China Daping Hospital of the Third Military Medical University Chongqing 630042China Department of Pathology of Anhui Medical University Hefei 230000China

The expression of immediate early gene plays a pivotal role in rat hepatocyte proliferation from G0 to G1 phases and the progression through G1 phase of the cell cycle within several hours after 2/3 hepatectomy. We investigated the different gene expressions within 1 h after 2/3 hepatectomy by representational difference analysis. Sequence analysis indicated that PC3 induced by NGF was a kind of immediate early gene and might be correlated with liver regeneration. Moreover, we found that 2/3 hepatectomy could induce the expressing of PC3 mRN A by Northern blot with a peak 1-2 h after surgery. In primary cultures of rat hepatocytes, addition of EGF resulted in rapid and transient induction of PC3 mRNA. It was first reported that PC3 gene belongs to immediate early gene associated with liver regeneration.

关键词： liver regeneration immediate early gene PC3 gene.